text: Calcium signaling in Arabidopsis is a calcium mediated signalling pathway that Arabidopsis plants use in order to respond to a stimuli. In this pathway, Ca works as a long range communication ion, allowing for rapid communication throughout the plant. Systemic changes in metabolites such as glucose and sucrose takes a few minutes after the stimulus, but gene transcription occurs within seconds. Because hormones, peptides and RNA travel through the vascular system at lower speeds than the plants response to wounds, indicates that Ca must be involved in the rapid signal propagation. Instead of local communication to nearby cells and tissues, Ca uses mass flow within the vascular system to help with rapid transport throughout the plant. Ca moving through the xylem and phloem acts through a “calcium signature” receptor system in cells where they integrate the signal and respond with the activation of defense genes. These calcium signatures encode information about the stimulus allowing the response of the plant to cater towards the type of stimulus.